Solved How to modify the data in the model and update the view when new data is received from external?
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@VInay123 said in How to modify the data in the model and update the view when new data is received from external?:
Actually in setData there is already a index.isValid() check.
index.isValid()
is an insufficient check, that's why checkIndex was introduced in Qt 5.11The indexes looks good and also the currentItem.
Unfortunately sometimes that's not enough. For example, if you forget to signal the view that you inserted a row, and then emit dataChanged for an item in that row, even if the item is 100% valid in the model the view will still think the row doesn't exist and do nothing
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@JonB @VRonin @SGaist : Something is not seeming right. I tried first to change the value using the following:
QModelIndex index = createIndex(0, 1, categories_[0]->entryAt(0)); this->setData(index, 11, Qt::EditRole);
And in delegate class i tried to see what the value it has but it looks like it is zero. Below is the implementation:
QWidget *PropertyEditorItemDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const { if (!index.isValid()) { return nullptr; } else if (index.column() == 0) { return QStyledItemDelegate::createEditor(parent, option, index); } const auto currentItem = static_cast<ScenarioPropertyItem *>(index.internalPointer()); switch (currentItem->itemType()) { case PropertyType::DOUBLE: { QDoubleSpinBox *box = new QDoubleSpinBox(parent); auto v = currentItem->data(index.column()); // Here it is zero??? :( box->setValue(v.toDouble()); return box; // qt will handle deletion } default: return QStyledItemDelegate::createEditor(parent, option, index); } }
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In setData could you add the
qDebug
as below and tell us what is printed?if (currentItem) { currentItem->setValue(value); qDebug() << currentItem->data(1); qDebug() << index.data(Qt::DisplayRole); emit dataChanged(index, index); return true; }
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@VRonin :
[16:56:03,236] [Debug] QVariant(int, 11) / My new values [16:56:03,237] [Debug] QVariant(int, 11) // My new values
;(
When i change via delegate:[16:58:06,173] [Debug] QVariant(double, 0) [16:58:06,176] [Debug] QVariant(double, 0)
I believe somewhere the indexes are not right. When i try to change the value(via delegate) of suppose "T" value so that i can iterate over parent and see the "S" value, here it is empty, but should be 11.
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My model looks like this:
In parent method i use pointer for parent item but not reference.
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@VRonin @SGaist @JonB : I just debugged to see that after changing the value of the property via delegate does the index in the following code has the same value.
QModelIndex index = createIndex(0, 1, categories_.at(0)->entryAt(0)); this->setData(index, 11, Qt::EditRole);
But it turns out that the index in the above is just a copy and when delegate changes the value it is not reflected in the index here. I think i am changing at a copy of the property but not the actual one.
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Can you show us the code for
Delegate::setModelData
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void PropertyEditorItemDelegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const { const auto currentItem = static_cast<ScenarioPropertyItem *>(index.internalPointer()); auto setup = [this, &model, &index](auto editor, auto usage) { if (editor) { usage(editor); } else { QStyledItemDelegate::setModelData(editor, model, index); } }; switch (currentItem->itemType()) { case PropertyType::DOUBLE: { setup(qobject_cast<QDoubleSpinBox *>(editor), [&index, &model](QDoubleSpinBox *editor) { editor->interpretText(); model->setData(index, editor->value(), Qt::EditRole); }); break; } case PropertyType::INTEGER: { setup(qobject_cast<QSpinBox *>(editor), [&index, &model](QSpinBox *editor) { editor->interpretText(); model->setData(index, editor->value(), Qt::EditRole); }); break; } case PropertyType::STRING: { setup(qobject_cast<QLineEdit *>(editor), [&index, &model](QLineEdit *editor) { model->setData(index, editor->text(), Qt::EditRole); }); break; } case PropertyType::BOOLEAN: { setup(qobject_cast<QComboBox *>(editor), [this, &index, &model](QComboBox *editor) { model->setData(index, editor->currentText(), Qt::EditRole); }); break; } default: QStyledItemDelegate::setModelData(editor, model, index); break; } }
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Why are you calling createIndex in
onRefreshRoadInfo
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@SGaist In onRefereshRoadInfo function i get the new values which has to be shown in the view. So, here I want to update the values, and as i dont have the index's, i create index for every property and call setData to update the values. If this is not correct how should i update the values here?
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Please show more patience, allow at least 24 hours before bumping your own thread. People answering on this forum do it on a voluntary basis and might not live in the same time zone as you.
That said, I stumble upon the QJsonModel project. You might want to check it.
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@SGaist I will keep in mind :). I saw the project and looks like my current implementation looks but, the project does not have the one thing i am looking for i.e. updating of data inside the code i.e. onRefereshRoadInfo.
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How is it possible that even after changing the model data value in a hard way and emitting reset model signals does not refresh the view.
void ScenarioPropertiesModel::onRefreshRoadInfo(const NewData& roadInfo) { emit beginResetModel(); categories_.at(0)->entryAt(0)->setValue(11111); emit endResetModel(); }
Could it be that index function implementation is wrong? This is my index implementation:
QModelIndex Model::index(int row, int column, const QModelIndex& parent /*= QModelIndex()*/) const { if (!hasIndex(row, column, parent)) { return QModelIndex(); } if (!parent.isValid()) { return createIndex(row, column, categories_.at(row).get()); } const auto currentCategory = static_cast<CategoryItem*>(parent.internalPointer()); ScenarioPropertyItem* currentItem = currentCategory->entryAt(row); if (currentItem) { return createIndex(row, column, currentItem); } else { return QModelIndex(); } }
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It still not clear to me in what component the problem is. Could you try to remove your custom delegate and see if it updates the values? if it doesn't then it's a model problem but at least we know where to focus
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@VRonin: Hi Ronin, thnx for the reply. Even without delegates it is not working. I believe it lies in model. I am updating a copy of the model but not the model.
Here below, the model pointer is always in the old state, even after changing the values in my model class.void Delegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index)
For infor: I have hosted the project in Github: https://github.com/vinayrajputh/qtmodelview
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@VInay123 said in How to modify the data in the model and update the view when new data is received from external?:
For infor: I have hosted the project in Github: https://github.com/vinayrajputh/qtmodelview
Would have been nice if it compiled. Can you upload the ui and json file too?
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@VRonin : Done.